Preparation and Bifunctional Gas Sensing Properties of Porous In₂O₃−CeO₂ Binary Oxide Nanotubes

Abstract

The porous binary In(2)O(3)-CeO(2) oxides nanotubes (NTs) in cubic phase were first fabricated by electrospinning (ESP) method and characterized by SEM, TEM, XRD, XPS and UV-vis absorption techniques. By adjusting the In(2)O(3) and CeO(2) molar ratio, the out diameters and wall thicknesses of the final composites were tuned ranging of 90-180 nm and 15-9 nm, respectively. The band gap of the binary oxides gradually decreases, and the ratio of Ce(3+) to Ce(4+) increases with the increase of CeO(2), implying that surface oxygen vacancies gradually increase. The gas sensing test reveals that when the content of CeO(2) is appropriate, the as fabricated In(2)O(3)-CeO(2) NTs could be bifunctional gas sensors to detect H(2)S at low temperature(25-110 °C) while acetone at relative high temperature (300 °C). The In(75)Ce(25) NTs sensor is an optimum one, which exhibits the highest response of 498 to H(2)S at 80 °C and the highest response of 30 to acetone at 300 °C. In contrast to the pure In(2)O(3) sensor, the response and recovery times, as well as the sensing reaction barrier height, for In(75)Ce(25) both degrade considerably. The above temperature-dependent sensing properties were attributed to two different gas sensing mechanisms, sulfuration at low temperature and adsorption at high temperature.

Ultrasensitive and ultraselective detection of H2S using electrospun CuO-loaded In2O3 nanofiber sensors assisted by pulse heating

“…Indium oxide (In 2 O 3 ) belongs to the class of wide-bandgap metal oxides, which represents an important class of gas-sensing materials for detecting harmful gases, such as H 2 S, NH 3 , and NO x [37]. It has been demonstrated that a decrease in size of the In 2 O 3 crystallites in the sensing layer can considerably enhance the response [38].…”

Microwave-assisted growth of In2O3 nanoparticles on WO3 nanoplates to improve H2S-sensing performance

“…But the SnO 2 nanoparticles were not evenly distributed on the surface of WO 3 lamella. In 2 O 3 is also a promising gas-sensing material especially to detect H 2 S. [33][34][35][36][37][38][39] The combination of WO 3 and In 2 O 3 nanocrystals, i.e., In 2 O 3 /WO 3 composite, can be expected to be an efficient gas-sensing system for gas detection but the In 2 O 3 /WO 3 composites reported were fabricated by simply mixing the solid-state precursor powders. 40,41 The microstructural control of the second phase is not available, and it is still a big challenge to achieve hierarchical In 2 O 3 /WO 3 nanocomposites.…”

Bimetallic oxamato complexes synthesized into mesoporous matrix as precursor to tunable nanosized oxide

“…Among these materials, there is a great interest in the synthesis of semiconductor oxides [2,3] and transition metal oxides [4], which can be used in extensive applications such as gas sensors, photochromic devices, and magnetic materials. Especially, various mixed transition metal oxides have been found very attractive in catalysis field [5].…”